Avoid unnecessary stores in readVarint on AArch64 #677
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Instead of storing result to memory at each byte iteration, we can keep temp result in a register and only write to memory once at the end. This reduces unnecessary memory stores and improves performance. Benchmark result without this patch: ============================================================================ [...]hrift/lib/cpp2/test/ProtocolBench.cpp relative time/iter iters/s ============================================================================ CompactProtocol_read_BigListBigInt 34.46us 29.02K Benchmark result with this patch: ============================================================================ [...]hrift/lib/cpp2/test/ProtocolBench.cpp relative time/iter iters/s ============================================================================ CompactProtocol_read_BigListBigInt 30.21us 33.10K Performance is uplifted by 14%.
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Instead of storing result to memory at each byte iteration, we can keep temp result in a register and only write to memory once at the end. This reduces unnecessary memory stores and improves performance.
Benchmark result without this patch:
[...]hrift/lib/cpp2/test/ProtocolBench.cpp relative time/iter iters/s
CompactProtocol_read_BigListBigInt 34.46us 29.02K
Benchmark result with this patch:
[...]hrift/lib/cpp2/test/ProtocolBench.cpp relative time/iter iters/s
CompactProtocol_read_BigListBigInt 30.21us 33.10K
Performance is uplifted by 14%.